code: def test_is_fitted(self):
      model = BaselineRegressorAlgorithm({"ml_task": "regression"})
      self.assertFalse(model.is_fitted())
      model.fit(self.X, self.y)
      self.assertTrue(model.is_fitted())
  
file_path: mljar-supervised/tests/tests_algorithms/test_baseline.py
imports: import unittest
  import tempfile
  import json
  import numpy
  import os
  import pandas
  from numpy.testing import assert_almost_equal
  from sklearn import datasets
  from supervised.algorithms.baseline import BaselineClassifierAlgorithm, BaselineRegressorAlgorithm
  from supervised.utils.metric import Metric
  import tempfile
label_desc: Use image node_id 5 for calling the BaselineTest obj's underlying member method code with example usage: obj.test_is_fitted() without return types